Tunable light sources are known in the art. WO2012095763, for instance, describes a tunable white light source, comprising at least one first light emitting diode (LED) adapted to emit light of a first integrated color point, at least one second light emitting diode adapted to emit light of a second integrated color point different from said first integrated color point, wherein said first and second integrated color points are selected such that the combined light output of the first and second light emitting diodes appears white in color, and a control unit for tuning a color temperature of white light output by said tunable white light source by adjusting the relative light output between said at least one first light emitting diode and said at least one second light emitting diode, wherein the control unit is configured to restrict the color temperature of the white light output by the tunable white light source to a tunable color temperature range where both the at least one first light emitting diode and the at least one second light emitting diode emit light for all color temperatures in the tunable color temperature range.
US2011317398 describes various embodiments providing a luminous device, including at least one semiconductor light source and at least one light-transmissive converter element including a wavelength-converting phosphor sensitive to the light emitted by the semiconductor light source, wherein the semiconductor light source can be at least partly covered by the converter element, and the converter element is movable such that a proportion of a light wavelength-converted by means of the converter element is adjustable depending on a position of the converter element.
WO2012121304 describes a light-emitting device which is so adapted that the whole of light emitted from a first LED and light emitted from a second LED is allowed to enter a common fluorescent member, and that synthetic light is emitted from the common fluorescent member, wherein the synthetic light contains and is synthesized from light which is emitted from the first LED in a wavelength-converted form, light which is emitted from the second LED in a wavelength-converted from, light which is produced by the wavelength conversion by the common fluorescent member, and light and light both of which pass through the common fluorescent member without undergoing the wavelength conversion by the common fluorescent member.
WO2010135927 describes a solid-state lighting device which includes a plurality of light-emitting elements configured for generating light that are thermally coupled to a heat spreading chassis configured for coupling to one or more heat sinks. The lighting device further includes a mixing chamber which is optically coupled to the plurality of light-emitting elements and configured to mix the light emitted by the plurality of light-emitting elements. A control system is operatively coupled to the plurality of light-emitting elements, and configured to control operation of the plurality of light-emitting elements.
WO2010032183 describes a color mixing method for consistent color quality. WO2013102820 describes a color tunable lighting assembly, a light source and a luminaire. Further, US20130120688 describes a color regulating device for illumination and apparatus using the same, and a method of regulating color.